Graphene/polypyrrole nanocomposites with high negative permittivity and low dielectric loss tangent

Abstract

Graphene (GNs)/ polypyrrole (PPy) nanocomposites with different content of GNs prepared by in-situ polymerization possess negative permittivity in the range of test frequency. Importantly, the GNs/PPy nanocomposites also have low dielectric loss tangent. ATR and XRD tests showed that no significant change in chemical bond and crystallization is found in GNs/PPy nanocomposites. SEM analysis indicated that GNs/PPy nanocomposites form different morphologies with the increase of GNs content. The negative permittivity of GNs/PPy nanocomposites is mainly caused by the plasmon resonance of the free electrons. The variation of resistivity and negative permittivity are basically consistent, which reflects that the good conductivity of the nanocomposites is attribute to the plasmon resonance of free electrons. The moderate addition of GNs is beneficial to the development of permittivity to a great negative value and decrease the dielectric loss tangent. The negative permittivity is up to −1.226 × 105 and the dielectric loss tangent is reduce to 0.32 in GNs/PPy nanocomposites with 10 wt% GNs content. The negative permittivity and the low dielectric loss tangent in GNs/PPy nanocomposites is achieved in a wider frequency range 1–1000 MHz.